1. Field of the Invention
The present invention generally relates to a device for determining the metered rate of granular materials such as seeds or fertilizer from an air seeder and, more particularly, is concerned with a device for collecting a plurality of metered air entrained streams of granular materials from an air seeder into a common sample for weighing. The plurality of metered streams are carried through a corresponding plurality of transfer conduits the downstream ends of which are grouped into a unit for either coupling with a corresponding grouped plurality of delivery conduits for distribution of the materials to the ground during normal operation or coupling with a sampling device for collection of the entire plurality of streams.
2. Description of the Related Art
In order to minimize seed and fertilizer costs while maximizing crop yield, it is necessary to uniformly distribute an optimum amount of seeds and fertilizer per acre of field. Presently available seed and fertilizer distribution implements typically utilize some form of adjustable metering device which is to be set according to manufacturer suggested settings for obtaining approximately the desired delivery rate of pounds of seed per acre.
Specific prior practices include the use of a plurality of metering wheels which deliver a corresponding plurality of metered seed streams from a seed supply. The metering wheels turn in response to forward movement of the farm implement and are geared so as to approximately meter the desired amount of seeds and fertilizer over the ground traversed by the implement. The gears may be adjusted according to manufacturer suggested settings in order to adjust the metered rates to correspond to changes in the type of seeds or fertilizers being applied or the quality of soil to be traversed. In addition to gearing the metering wheels according to a manufacturer's suggested setting, attempts to obtain a metered rate approximating the desired optimum rate have involved collecting a sample from one of the plurality of seed streams, estimating the entire application rate by multiplying the sampled rate by the entire number of seed streams and then adjusting the gears until this estimated entire application rate equals to the desired optimum rate.
The cited prior practices have a number of problems or shortcomings. Relying entirely upon manufacturer suggested settings for determining the gear setting necessary to apply the desired optimum rate of seeds or fertilizer can result in actual application rates differing substantially from the desired optimum rate due to variations in the types and conditions of materials being metered. Furhermore, the prior practice of adjusting the estimated entire application rate until it approaches the desired optimum rate can also result in a substantial difference between the actual application rate and the desired optimum rate due to variations in flow rates among the plurality of seed streams. Furthermore, simultaneous sampling of all of the seed streams of the prior distribution devices at their outlets would be somewhat difficult due to the typically large number of streams involved and due to the discharge points for those streams being at spaced apart locations across the entire width of the furrow opening implement.
Consequently, a need exists for improvements in seed and fertilizer metering devices which will provide for a determination of the actual seed and fertilizer distribution rates and adjustment thereof.